Portable screen assemblies are well known and widely used. Assembly is typically tedious, involving setting up a stand and unrolling the projection screen. Such assemblies typically need to provide a sizable viewing area for projection equipment, and as a result are generally large and bulky and do not to break down to a very compact size. When fully assembled, the projection screen is seldom completely perpendicular with the image cast on it by projection equipment. Consequently, the image being displayed is distorted. Furthermore, conventional portable projection screen assemblies tend to lack sturdiness.
Various attempts have been made to address some of these deficiencies. U.S. Pat. No. 3,205,772 issued to Guske discloses a portable screen assembly with a keystone eliminator for relieving distortion of the image shown on the screen. Such distortion is a result of the projected image being cast on the projection screen at an angle of incidence of more or less than 90°. Linear distortion such as this can be eliminated by correcting the angle of the screen so that the projected image is cast at approximately a right angle to the screen. This notch and hook form of keystone eliminating device provides relief for keystoning effects on roller mounted screens only.
U.S. Pat. No. 4,068,921 issued to Okumura discloses a projector screen mounted on rollers and which has a support means that can be stored within the rollers. Such a device cannot be stored compactly, and is bulky and impractical.
Several deficiencies are common to the above attempts to provide a tilting screen that eliminates distortion of the image cast on a portable projection screen. The tilting mechanism in the above designs eliminates distortion on screens that are mounted on a roller device. Projector assemblies that do not include roller mounted screens do not benefit from this design.
U.S. Pat. No. 3,942,869 issued to Portner discloses a projection screen unit with cross rods attached to a central pole considerably near the center of the projection screen. The projection screen has the capability to be tilted thus eliminating distortion on the screen. However, the support for this projection screen assembly does not provide a means by which to tilt the screen.
U.S. Pat. No. 4,317,553 issued to Helmut Meinunger, discloses a stand with a guide body which moves up a central post providing for angular displacement of the legs. The guide body holds the legs in place when set to the desired position. However, the device cannot be collapsed very compactly.
U.S. Pat. No. 4,017,152 issued to Allen discloses a portable projection screen with a central hub member that has multiple extensible-contractible rods which radiate outwardly from it. The rods attach to the screen at the corners of the screen. This design is complicated to assemble.
U.S. Pat. No. 3,592,255 issued to Potter et al. discloses a projector screen that hangs vertically from a ceiling or wall. This design incorporates an extended stretch arm to keep the screen open for use. Such a design is impractical with respect to portability.
U.S. Pat. No. 4,110,003 issued to Zinn discloses a projector screen mounted on rollers and which has a support means that can be stored within the rollers. Such rollers do not collapse compactly.
U.S. Pat. No. 6,249,377 discloses a projection screen unit with support rails which keep two separate frames apart during use. One frame has a screen fixedly mounted to it while the second frame is rotatably mounted to a spring-biased roll attached to the projection screen. When collapsed, the projection screen winds around the roll attached to the second frame, and is thus not very compact.
U.S. Pat. No. 5,581,401 issued to Takamoto et al. discloses yet another projector screen mounted on rollers and which has a support means that can be stored within the rollers. The mechanism disclosed by Takamoto includes legs which hold the projector screen in place when in a full viewing position.
Similarly, U.S. Pat. No. 6,191,886 issued to Sinkoff discloses a video projection screen assembly which has a roller mounted screen attached to a support assembly with one or more gas spring arms for opening the screen when expanded from its collapsed position. The support assembly in this design is not removably attached to the screen.
Likewise, U.S. Pat. No. 3,841,594 issued to Zinn discloses a collapsible roller mounted projection screen. The screen, when fully collapsed, must still be stored in an area at least as large as the width of the projector screen itself.
In each of the above attempts to provide a compact design for a projector screen assembly, a common problem exists. In each of the above instances, the roller mounted projector screen assembly must maintain the overall width of the screen when broken down into its compact portable state.
It would be advantageous to provide a portable screen assembly that can be erected quickly and easily, has the ability to tilt the angle of the screen to eliminate distortion of the image being displayed, and can be packed into a small case for ease in mobility.